A seatbelt pretensioner is known as one of the safety systems to protect a vehicle occupant from the shock in a car collision. The seatbelt pretensioner is brought into action by a large amount of high-temperature and high-pressure gas emitted from the gas generator, for the protection of the vehicle occupant. The gas generator includes an igniter device and gas generant and is structured so that when a car collision happens, the igniter device is brought into action to ignite and burn the gas generant, to thereby generate the large amount of gas rapidly.
The gas generator shown in FIG. 10, taken as an example of the conventional gas generator, is known (Cf. Patent Document 1, for example). The gas generator shown in FIG. 10 comprises a gas generant 102 charging cup 103, an igniter device (squib) 105 comprising an enhancer agent storage holder 105g containing an enhancer agent 105a, and a holder 106 on which the igniter device 105 and the cup 103 are crimped to contain the gas generant 102 in a sealing manner. In the igniter device 105, two electrode pins 105d, standing vertically to allow electricity to pass through under signals from sensors, not shown, are formed to be integral with a body 105b formed of resin. A resistance element 105f is bridged between tips of the electrode pins 105d and is covered with a firing agent 105c contacting with the enhancer agent 105a. 
The holder 106 assembled in a seatbelt pretensioner and the like is formed of material resistant to internal pressure, such as iron and aluminum, so that when the gas generator is brought into action, the gas generator can be prevented from being burst as a result of internal pressure.
Also, an O-ring 110 is disposed in a space between the holder 106 and the igniter device 105, to prevent infiltration of moisture from outside. Further, a shorting clip 108 is fitted in the holder 106, to keep the two electrode pins 105d of the igniter device 105 in a short-circuited state, so as to prevent malfunction as a result of static electrical charge and the like.
When the gas generator 101 receives signals from sensors, not shown, the resistance element 105f provided in the igniter device 105 generates heat, first, and, then, the firing agent 105f is fired. Then, the flames of the firing agent 105f fire the enhancer agent 105a, followed by ignition and burning of the gas generant 102 as a result of the flames of the enhancer agent 105a, then generating a large amount of gases rapidly.
As shown in FIG. 10, in the igniter device 105 of the conventional gas generator 101, the resin body 105b and the electrode pins 105d are formed integrally. Also, the electrode pins 105d are previously distorted in the body 105b, to ensure a stable fixation of the electrode pins before and after the action of the gas generator 101.
Patent Document 1: JP Unexamined Patent Application 2001-260815 (FIGS. 1, 12)